Physical Port Sharing in a Link Aggregation Group

1. A computer program product, comprising: a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: establishing a plurality of virtual switches in a host system of a computing environment, each virtual switch of the plurality of virtual switches comprising a respective virtual switch port grouped within a shared port group of virtual switch ports, wherein the virtual switch ports of the shared port group are in communication with a common physical network adapter of multiple physical network adapters of the host system; and sharing, by the virtual switch ports of the shared port group, a single physical port of the physical network adapter as part of a common physical link aggregation group (LAG) comprising the multiple physical network adapters of the host system as members of the common physical LAG.

2. The computer program product of claim 1 , wherein the plurality of virtual switches are dispersed within multiple logical partitions of the host system, and wherein the method further comprises providing LAG virtualization components within the multiple logical partitions, wherein the LAG virtualization components of the multiple logical partitions communicate with each other to facilitate administration of a link aggregation control protocol (LACP) and LAG marker protocol of the physical LAG based on shared port group configuration information and based on virtual switch network connection status information from the physical network adapter.

3. The computer program product of claim 1 , wherein the method further comprises deploying, at least in part by a virtual switch port of the shared port group, the physical LAG by establishing a network connection to the physical network adapter and initiating transitioning of the physical network adapter into a port group membership control mode in which the shared port group is registered with the physical network adapter for participation within the physical LAG.

4. The computer program product of claim 1 , wherein a virtual switch port of the shared port group serves as an active LAG port controller of the single physical port, the active LAG port controller performing link aggregation control protocol (LACP) management and LAG marker management for the physical LAG on behalf of the shared port group, and wherein one or more other virtual switch ports of the shared port group serve as one or more standby LAG port controllers for taking over as the active LAG port controller if requested.

5. The computer program product of claim 4 , wherein the LAG marker management comprises coordinating, by the active LAG port controller in response to receipt of a LAG marker protocol data unit (PDU) communication from the physical network adapter, LAG marker PDU responses sent in response to the LAG marker PDU communication, the LAG marker PDU responses being sent from the one or more standby LAG port controllers of the shared port group, wherein the one or more standby LAG port controllers provide the LAG marker PDU responses to the active LAG port controller and the active LAG port controller awaits receipt of a LAG marker PDU response from each standby LAG port controller of the one or more standby LAG port controllers of the shared port group.

6. The computer program product of claim 5 , wherein the method further comprises, based on the active LAG port controller receiving a LAG marker PDU response from each standby LAG port controller of the one or more standby LAG port controllers of the shared port group, generating and sending, by the active LAG port controller, a LAG marker PDU response to the physical network adapter responding to the LAG marker PDU communication.

7. The computer program product of claim 4 , wherein the active LAG port controller and the one or more standby LAG port controllers concurrently send and receive data through the single physical port in communicating data of the physical LAG.

8. The computer program product of claim 4 , wherein each standby LAG port controller of the one or more standby LAG port controllers of the shared port group receives LACP protocol transmissions from the physical network adapter or from the active LAG port controller and maintains at least some information of the LACP protocol transmissions to facilitate taking over as the active LAG port controller.

9. The computer program product of claim 8 , wherein the method further comprises, based on an indication from the physical network adapter: assuming responsibility, by a standby LAG port controller of the one or more standby LAG port controllers, as active LAG port controller for the shared port group, wherein the standby LAG port controller becomes the active LAG port controller for the group, and wherein performance of LACP management and LAG marker management for the physical LAG on behalf of the shared port group transitions to the standby LAG port controller that assumes responsibility as the active LAG port controller; and presenting, by the active LAG port controller, to a partner switch to which the physical network adapter is connected, a same port identifier as that presented by the previous active LAG port controller, to facilitate transitioning of the LACP management and LAG marker management to the active LAG port controller transparent to the partner switch.

10. The computer program product of claim 1 , wherein the shared port group comprises a first shared port group and the physical network adapter comprises a first physical network adapter of the multiple physical network adapters of the host system, and wherein the method further comprises establishing a second shared port group comprising other virtual switch ports of the plurality of virtual switches, different from the virtual switch ports of the first shared port group, wherein each virtual switch port of the second shared port group shares a single physical port of a second physical network adapter of the multiple physical network adapters, the second physical network adapter being different from the first physical network adapter, and wherein the first physical network adapter and the second physical network adapter are part of the common physical LAG.

11. A system comprising: a memory; and a processor in communications with the memory, wherein the system is configured to perform a method, the method comprising: establishing a plurality of virtual switches in a host system of a computing environment, each virtual switch of the plurality of virtual switches comprising a respective virtual switch port grouped within a shared port group of virtual switch ports, wherein the virtual switch ports of the shared port group are in communication with a common physical network adapter of multiple physical network adapters of the host system; and sharing, by the virtual switch ports of the shared port group, a single physical port of the physical network adapter as part of a common physical link aggregation group (LAG) comprising the multiple physical network adapters of the host system as members of the common physical LAG.

12. The system of claim 11 , wherein the plurality of virtual switches are dispersed within multiple logical partitions of the host system, and wherein the method further comprises providing LAG virtualization components within the multiple logical partitions, wherein the LAG virtualization components of the multiple logical partitions communicate with each other to facilitate administration of a link aggregation control protocol (LACP) and LAG marker protocol of the physical LAG based on shared port group configuration information and based on virtual switch network connection status information from the physical network adapter.

13. The system of claim 11 , wherein the method further comprises deploying, at least in part by a virtual switch port of the shared port group, the physical LAG by establishing a network connection to the physical network adapter and initiating transitioning of the physical network adapter into a port group membership control mode in which the shared port group is registered with the physical network adapter for participation within the physical LAG.

14. The system of claim 11 , wherein a virtual switch port of the shared port group serves as an active LAG port controller of the single physical port, the active LAG port controller performing link aggregation control protocol (LACP) management and LAG marker management for the physical LAG on behalf of the shared port group, and wherein one or more other virtual switch ports of the shared port group serve as one or more standby LAG port controllers for taking over as the active LAG port controller if requested.

15. The system of claim 14 , wherein the LAG marker management comprises coordinating, by the active LAG port controller in response to receipt of a LAG marker protocol data unit (PDU) communication from the physical network adapter, LAG marker PDU responses sent in response to the LAG marker PDU communication, the LAG marker PDU responses being sent from the one or more standby LAG port controllers of the shared port group, wherein the one or more standby LAG port controllers provide the LAG marker PDU responses to the active LAG port controller and the active LAG port controller awaits receipt of a LAG marker PDU response from each standby LAG port controller of the one or more standby LAG port controllers of the shared port group.

16. The system of claim 15 , wherein the method further comprises, based on the active LAG port controller receiving a LAG marker PDU response from each standby LAG port controller of the one or more standby LAG port controllers of the shared port group, generating and sending, by the active LAG port controller, a LAG marker PDU response to the physical network adapter responding to the LAG marker PDU communication.

17. The system of claim 14 , wherein each standby LAG port controller of the one or more standby LAG port controllers of the shared port group receives LACP protocol transmissions from the physical network adapter or from the active LAG port controller and maintains at least some information of the LACP protocol transmissions to facilitate taking over as the active LAG port controller, and wherein the method further comprises, based on an indication from the physical network adapter: assuming responsibility, by a standby LAG port controller of the one or more standby LAG port controllers, as active LAG port controller for the shared port group, wherein the standby LAG port controller becomes the active LAG port controller for the group, and wherein performance of LACP management and LAG marker management for the physical LAG on behalf of the shared port group transitions to the standby LAG port controller that assumes responsibility as the active LAG port controller; and presenting, by the active LAG port controller, to a partner switch to which the physical network adapter is connected, a same port identifier as that presented by the previous active LAG port controller, to facilitate transitioning of the LACP management and LAG marker management to the active LAG port controller transparent to the partner switch.

18. The computer program product of claim 1 , wherein the common physical LAG remains compatible with an Institute of Electrical and Electronics Engineers (IEEE) link aggregation group specification.

19. The system of claim 11 , wherein the common physical LAG remains compatible with an Institute of Electrical and Electronics Engineers (IEEE) link aggregation group specification.